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- First, let's learn the obesity definition.
- Next, we will look at the causes of obesity.
- We'll continue by exploring 3 factors that influence obesity.
- Then, what are some psychological explanations of obesity?
- Finally, we will learn more about morbidity obesity.
Obesity Definition
Cardiovascular disease is becoming or already is the leading cause of death in many countries. We can begin to understand why obesity is a major cause for concern.
Obesity is a condition in which a person is identified as overweight with an accumulation of body fat. Excess body weight, typically 20% or more above a person's ideal body weight, may indicate obesity.
Obesity can lead to an increased risk of disease, disability, or in some instances, death. Obesity can result from a poor diet, lack of physical activity, or an underlying condition. Sometimes all of these factors can be present at the same time.
People begin to gain weight when they eat more calories than they burn. If this is the case, it will eventually lead to significant weight gain over a long time.
Causes of Obesity
Several factors can lead to obesity. Lack of physical activity can lead to obesity because energy from food is stored as fat because it is not used. The Department of Health and Human Services recommends that adults engage in at least 150 minutes of physical activity per week, such as walking, running, or bicycling, and this time can be spread out over the week, such as in 30-minute sessions five days per week.
Foods high in fat and sugar can lead to excess weight being stored. Examples include processed food, fast food, sugary drinks, and alcoholic drinks.
Fig. 1 Too much processed foods like candy can lead to weight gain.
Obesity: Side Effects
Obesity puts a significant strain on the body, and your organs must work extra hard to do what they need to do. Some side effects of this are:
Physical health problems.
Mental illness.
Low energy.
Lower self-esteem and self-confidence.
Difficulties at work.
Difficulties in personal relationships.
Difficulties with travel.
Challenges in performing physical activities.
As mentioned earlier, cardiovascular diseases (such as heart disease and stroke) are one of the main risk factors for those with a high BMI (body mass index). In 2012, they were the leading cause of death, according to WHO.
3 Factors That Influence Obesity
Several biological reasons may explain an increased likelihood of obesity. These medical reasons include genetics, hormones, medications, appetite control, and other physical health conditions.
Obesity: Genetics
Certain genetic traits can make it harder for a person to lose weight or make them more prone to gaining weight. In rare cases, genetic conditions such as Prader-Willi syndrome can lead to obesity.
Prader-Will Syndrome is a genetic illness that causes many physical, behavioural and mental issues. It is characterised by many symptoms, e.g. low muscle tone, cognitive dysfunction, irregularities in growth, etc.
Even though genetic traits can make it difficult to lose weight, this does not mean it is impossible to lose weight.
In addition, Frayling et al. (2007) identified a gene associated with fat mass and obesity. This gene is also known as the FTO gene. It was found that people with two copies of this gene have a 70% increased risk of obesity.
Stunkard et al. (1986) found that when obesity rates in Danish adopted children were compared with those of their biological parents and those of their adoptive parents, there was a strong relationship between the biological cases.
There was no relationship between adopted children and their adoptive parents, suggesting genetics plays a role in weight management in adulthood.
Like all biological arguments, genetic arguments have a problem with reductionism that you should consider when using studies like this.
We also need to consider how generalisable the results are, as one country's results may not reflect anothers.
Obesity: Evolutionary Explanation
Neel (1962) proposed an evolutionary explanation for obesity that is related to the genetic explanation of obesity. This explanation is called the 'thrifty gene hypothesis'.
He proposed that our ancestors ate large amounts of food, including fatty and sugary foods, to store energy and ensure survival. When food supplies were scarce, those who could store body fat were more likely to survive and pass on their genes.
In modern times we no longer face such shortages, and overeating leads to weight problems.
Appetite Control Issues in Obesity
Ghrelin and leptin are hormones involved in the control of eating behaviour.
Studies such as that by Klok et al. (2007) have found that obese patients may be leptin resistant. Obese people tend to have high leptin levels and are resistant to exogenous sources of leptin (as many originally thought leptin would reduce feelings of hunger and be a possible treatment plan for obese people).
It appears leptin cannot fully exert its effects in obese people; therefore, they have difficulty achieving a feeling of fullness, which may be associated with overeating.
The hypothalamus ultimately controls eating behaviour, as we discussed in our article on controlling eating behaviours. The ventromedial hypothalamus (VMH) regulates food and tells you to stop eating when hormones indicate you are full.
Dysfunction of the VMH can lead to obesity, as studies have shown lesions in this area can lead to overeating and problems regulating food intake.
Psychological Explanations of Obesity
Psychological explanations for obesity examine how various mental health, environmental, and social factors can lead to obesity. Psychological explanations for obesity may also be closely linked to biological causes of obesity.
Obesity: The Boundary Model
Herman and Polivy (1983) developed the boundary model. It assumes that certain parameters psychologically explain a person's desire to eat and the associated biological pressures.
There is a biological process behind man's need and desire for food.
Hunger causes one to eat the minimum amount of food needed to survive. A feeling of satiety eventually sets in when you eat this, signalling you to stop eating.
Your environment influences the span between hunger and satiety.
Overall, the boundary model represents a scale between hunger and satiety. There is a minimum (hunger) and a maximum (satiety). In obesity, problems arise when the range is not maintained, which is where restraint theory comes into play.
Obesity: Restraint Theory
If you have ever dieted or dealt with people who have dieted, you may have seen this phenomenon in action or even experienced it yourself. Restraint theory states that when you try to restrict or stop eating, you eat more than if you did not.
This is due to a cognitive boundary that dieters have introduced that, when crossed, causes a state of disinhibition regardless of where you are on the hunger/satiety scale.
Fig. 2 Dietary limitations can lead to diet failure.
Restrained eating is based on the understanding that you will not exceed this self-imposed cognitive dietary limit. Exceeding this limit leads to disinhibition, where the dieter basically gives up and decides to eat without restriction because there is no longer any point in trying. This can go beyond satiety, allowing them to eat more despite being full.
Dieters may also lose the ability to recognise their own body's signals to start and stop eating. If restrained eaters constantly exceed their satiety limit, they may become obese.
Obesity: Mental Health Explanations
Mental health conditions can lead to various symptoms, such as increased appetite, sleep problems, decreased energy, disruption of hormone levels, and decreased activity, which can contribute to weight gain and obesity.
Poor problem-solving skills are also associated with an inability to keep track of eating and to refrain from overeating.
Such mental health issues and conditions include:
| Condition | Effects |
Depression can lead to obesity or occur as a result of obesity. Low mood, loneliness, decreased activity, self-confidence, sleep disturbances, and low self-esteem can trigger stress and biological responses that lead to weight gain and obesity. | |
Stress can affect eating behaviours. For some people, stress can cause them to consume fewer calories. For others, stress can lead to increased appetite, consumption of high-calorie foods, and sleep disturbances. Stress also disrupts hormone balance, affecting leptin, cortisol and other hormones associated with weight gain and obesity. | |
Anxiety | Anxiety can affect stress levels, causing a person's body to respond and be more prone to weight gain and obesity. |
Binge-Eating Disorder | In binge eating, a person suddenly eats excessive amounts of food, especially high-calorie food. Binge eating can lead to obesity. Binge eating is also associated with bulimia, which involves binge eating followed by vomiting. People with bulimia may also develop obesity. Factors leading to binge eating or bulimia include body dissatisfaction, low self-esteem, stress eating, loneliness, shame, and depression. |
Other psychological explanations include social factors such as learned behaviours from family members and cultural norms. Environmental factors such as financial income may come into play, making higher-calorie foods cheaper and more readily available.
Morbidity Obesity
Morbid obesity may also be referred to as severe obesity.
Morbid obesity is a condition in which the calculated BMI is greater than 35 and is associated with at least one medical condition.
It is important to know that BMI is not infallible. When a muscular person, such as a bodybuilder or someone who goes to the gym, gets their BMI results, it would not be surprising if they were classified as obese. This is because BMI is simply a measurement tool that does not accurately indicate fat percentage and does not take muscle into account.
Morbid obesity can affect bodily functions and be associated with serious health problems, such as:
Hypertension.
Type 2 diabetes.
Sleep apnea.
Heart disease.
Stroke.
Reproductive problems.
Gallstones.
Cancer.
It is estimated that 1 in 4 adults in the UK is obese. A 2017 European Society of Cardiology study estimated that British adults are less physically active, consume less fruit and vegetables, and consume more sugar than other European countries.
Obesity - Key takeaways
Obesity definition is a condition in which a person is identified as overweight with an accumulation of body fat.
Obesity symptoms can include physical illness, such as cardiovascular diseases (one of the leading causes of death in many countries), mental illness, low energy and low self-esteem.
Morbid obesity can affect bodily functions and be associated with severe health problems.
Biological causes of obesity include genetic predisposition (FTO gene), biological links between family members, evolutionary origins, medication problems, and appetite problems (ghrelin and leptin).
The psychological explanations of obesity are the boundary model and restraint theory.
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Frequently Asked Questions about Obesity
What is the hormonal cause of obesity?
Hormones are one of the biological reasons that can explain an increased likelihood of obesity. Ghrelin and leptin are hormones involved in controlling eating behaviour.
For example, stress can disrupt hormone levels, affecting leptin, cortisol and other hormones which have also been linked to weight gain and obesity.
Is obesity a disease?
Obesity is a condition in which a person is identified as overweight with an accumulation of body fat. Obesity has become a pandemic in itself, according to some scientists, with about 1.9 billion people worldwide overweight and at least 650 million obese in 2016, according to the World Health Organisation.
What determines obesity?
Excess body weight, typically 20% or more above a person's ideal body weight, may indicate obesity.
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